How much easier?

Like "turn key" easier?

Like in "everything done by someone else" easier?

By the way "two ways of sine wave measurements" - you sure there are only two ways?

Next thing. If you think you need to clamp when feding sine wave directly - wouldn't you have same need to clamp if you rectify? Especially since you seem to talk about clamping on the positive side - not clamping of negative half-cycle.

A big factor her is of course what sampling rate you can manage - and what frequency the sine wave has.

And if you "lift" the sine wave with a DC component, so the negative half-period is also within the ADC range or if your ADC can measure negative values. Or if you just cut away the negative half-period.

But going back to the origin - your subject is "Sine wave detection" - i.e. not measurement of amplitud or frequency but just detecting if there is a sine wave. Aren't there yet more alternatives then? Especially if it isn't important to reject sine waves with strong overtone components.